The invention relates to a catalyst for the hydroconversion of asphaltene-containing hydrocarbonaceous charge stocks. More specifically, the invention relates to a catalyst prepared by the steps which comprise: (a) adding to an asphaltene-containing hydrocarbonaceous oil charge stock a metal compound, a heteropoly acid and water; (b) converting the metal compound and heteropoly acid within the charge stock by heating the oil to a temperature from about 120.degree. F. (43.degree. C.) to about 500.degree. F. (260.degree. C.) to produce at least one organometallic compound within the charge stock; and (c) converting the organometallic compound within the charge stock under hydroconversion conditions to produce the catalyst.